Project Updates

Lowered water levels effects on Cranberry Bog State Nature Preserves

ODNR Division of Parks and Recreation's Chief Botanist offers his observations on the effects of lowered lake levels on Cranberry Bog State Nature Preserves.

The drawdown of the lake will decrease the decomposition of peat by the well-oxygenated lake waters that surround it.

The lower lake levels will significantly reduce wave and ice action that has been, and continues to be, factors contributing to the deterioration of the bog.

After drawdown, Department botanists and ecologists will continue monitoring the condition of the bog on a regular basis to locate any signs of stress on the rare ecosystem.

The drawdown will aid in anchoring the bog, decreasing the potential of segments of the bog from tearing away from the island.

The bog environment created by sphagnum peat moss will continue to function and possibly improve bog conditions by reducing the negative impacts of the well-oxygenated lake waters.

The drawdown will aid in stabilizing the deterioration of the bog by the lower water level of nutrient rich waters surrounding the bog.

Bogs are oxygen deficient, acidic wetlands. The high acidity minimizes the presence of microscopic organisms that decompose dead plant material. Consequently, rather than decaying and enriching the water with nutrients, dead vegetation, primarily sphagnum, builds up and compacts. The nutrient rich waters of the lake deteriorate the bog mat.

The sphagnum mat acts like a sponge and draws up and holds water. This function will continue after the drawdown.